include/linux/spinlock.h - kernel/msm-4.19 - Gitiles

 #ifndef __LINUX_SPINLOCK_H
 #define __LINUX_SPINLOCK_H

 /*
  * include/linux/spinlock.h - generic spinlock/rwlock declarations
  *
  * here's the role of the various spinlock/rwlock related include files:
  *
  * on SMP builds:
  *
  *  asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
  *                        initializers
  *
  *  linux/spinlock_types.h:
  *                        defines the generic type and initializers
  *
  *  asm/spinlock.h:       contains the __raw_spin_*()/etc. lowlevel
  *                        implementations, mostly inline assembly code
  *
  *   (also included on UP-debug builds:)
  *
  *  linux/spinlock_api_smp.h:
  *                        contains the prototypes for the _spin_*() APIs.
  *
  *  linux/spinlock.h:     builds the final spin_*() APIs.
  *
  * on UP builds:
  *
  *  linux/spinlock_type_up.h:
  *                        contains the generic, simplified UP spinlock type.
  *                        (which is an empty structure on non-debug builds)
  *
  *  linux/spinlock_types.h:
  *                        defines the generic type and initializers
  *
  *  linux/spinlock_up.h:
  *                        contains the __raw_spin_*()/etc. version of UP
  *                        builds. (which are NOPs on non-debug, non-preempt
  *                        builds)
  *
  *   (included on UP-non-debug builds:)
  *
  *  linux/spinlock_api_up.h:
  *                        builds the _spin_*() APIs.
  *
  *  linux/spinlock.h:     builds the final spin_*() APIs.
  */

 #include <linux/preempt.h>
 #include <linux/linkage.h>
 #include <linux/compiler.h>
 #include <linux/thread_info.h>
 #include <linux/kernel.h>
 #include <linux/stringify.h>
 #include <linux/bottom_half.h>

 #include <asm/system.h>

 /*
  * Must define these before including other files, inline functions need them
  */
 #define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME

 #define LOCK_SECTION_START(extra)               \
         ".subsection 1\n\t"                     \
         extra                                   \
         ".ifndef " LOCK_SECTION_NAME "\n\t"     \
         LOCK_SECTION_NAME ":\n\t"               \
         ".endif\n"

 #define LOCK_SECTION_END                        \
         ".previous\n\t"

 #define __lockfunc fastcall __attribute__((section(".spinlock.text")))

 /*
  * Pull the raw_spinlock_t and raw_rwlock_t definitions:
  */
 #include <linux/spinlock_types.h>

 extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);

 /*
  * Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
  */
 #ifdef CONFIG_SMP
 # include <asm/spinlock.h>
 #else
 # include <linux/spinlock_up.h>
 #endif

 #ifdef CONFIG_DEBUG_SPINLOCK
   extern void __spin_lock_init(spinlock_t *lock, const char *name,
 			       struct lock_class_key *key);
 # define spin_lock_init(lock)					\
 do {								\
 	static struct lock_class_key __key;			\
 								\
 	__spin_lock_init((lock), #lock, &__key);		\
 } while (0)

 #else
 # define spin_lock_init(lock)					\
 	do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
 #endif

 #ifdef CONFIG_DEBUG_SPINLOCK
   extern void __rwlock_init(rwlock_t *lock, const char *name,
 			    struct lock_class_key *key);
 # define rwlock_init(lock)					\
 do {								\
 	static struct lock_class_key __key;			\
 								\
 	__rwlock_init((lock), #lock, &__key);			\
 } while (0)
 #else
 # define rwlock_init(lock)					\
 	do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
 #endif

 #define spin_is_locked(lock)	__raw_spin_is_locked(&(lock)->raw_lock)

 /**
  * spin_unlock_wait - wait until the spinlock gets unlocked
  * @lock: the spinlock in question.
  */
 #define spin_unlock_wait(lock)	__raw_spin_unlock_wait(&(lock)->raw_lock)

 /*
  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
  */
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 # include <linux/spinlock_api_smp.h>
 #else
 # include <linux/spinlock_api_up.h>
 #endif

 #ifdef CONFIG_DEBUG_SPINLOCK
  extern void _raw_spin_lock(spinlock_t *lock);
 #define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
  extern int _raw_spin_trylock(spinlock_t *lock);
  extern void _raw_spin_unlock(spinlock_t *lock);
  extern void _raw_read_lock(rwlock_t *lock);
  extern int _raw_read_trylock(rwlock_t *lock);
  extern void _raw_read_unlock(rwlock_t *lock);
  extern void _raw_write_lock(rwlock_t *lock);
  extern int _raw_write_trylock(rwlock_t *lock);
  extern void _raw_write_unlock(rwlock_t *lock);
 #else
 # define _raw_spin_lock(lock)		__raw_spin_lock(&(lock)->raw_lock)
 # define _raw_spin_lock_flags(lock, flags) \
 		__raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
 # define _raw_spin_trylock(lock)	__raw_spin_trylock(&(lock)->raw_lock)
 # define _raw_spin_unlock(lock)		__raw_spin_unlock(&(lock)->raw_lock)
 # define _raw_read_lock(rwlock)		__raw_read_lock(&(rwlock)->raw_lock)
 # define _raw_read_trylock(rwlock)	__raw_read_trylock(&(rwlock)->raw_lock)
 # define _raw_read_unlock(rwlock)	__raw_read_unlock(&(rwlock)->raw_lock)
 # define _raw_write_lock(rwlock)	__raw_write_lock(&(rwlock)->raw_lock)
 # define _raw_write_trylock(rwlock)	__raw_write_trylock(&(rwlock)->raw_lock)
 # define _raw_write_unlock(rwlock)	__raw_write_unlock(&(rwlock)->raw_lock)
 #endif

 #define read_can_lock(rwlock)		__raw_read_can_lock(&(rwlock)->raw_lock)
 #define write_can_lock(rwlock)		__raw_write_can_lock(&(rwlock)->raw_lock)

 /*
  * Define the various spin_lock and rw_lock methods.  Note we define these
  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
  * methods are defined as nops in the case they are not required.
  */
 #define spin_trylock(lock)		__cond_lock(lock, _spin_trylock(lock))
 #define read_trylock(lock)		__cond_lock(lock, _read_trylock(lock))
 #define write_trylock(lock)		__cond_lock(lock, _write_trylock(lock))

 #define spin_lock(lock)			_spin_lock(lock)

 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 # define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
 #else
 # define spin_lock_nested(lock, subclass) _spin_lock(lock)
 #endif

 #define write_lock(lock)		_write_lock(lock)
 #define read_lock(lock)			_read_lock(lock)

 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)

 #define spin_lock_irqsave(lock, flags)	flags = _spin_lock_irqsave(lock)
 #define read_lock_irqsave(lock, flags)	flags = _read_lock_irqsave(lock)
 #define write_lock_irqsave(lock, flags)	flags = _write_lock_irqsave(lock)

 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 #define spin_lock_irqsave_nested(lock, flags, subclass) \
 	flags = _spin_lock_irqsave_nested(lock, subclass)
 #else
 #define spin_lock_irqsave_nested(lock, flags, subclass) \
 	flags = _spin_lock_irqsave(lock)
 #endif

 #else

 #define spin_lock_irqsave(lock, flags)	_spin_lock_irqsave(lock, flags)
 #define read_lock_irqsave(lock, flags)	_read_lock_irqsave(lock, flags)
 #define write_lock_irqsave(lock, flags)	_write_lock_irqsave(lock, flags)
 #define spin_lock_irqsave_nested(lock, flags, subclass)	\
 	spin_lock_irqsave(lock, flags)

 #endif

 #define spin_lock_irq(lock)		_spin_lock_irq(lock)
 #define spin_lock_bh(lock)		_spin_lock_bh(lock)

 #define read_lock_irq(lock)		_read_lock_irq(lock)
 #define read_lock_bh(lock)		_read_lock_bh(lock)

 #define write_lock_irq(lock)		_write_lock_irq(lock)
 #define write_lock_bh(lock)		_write_lock_bh(lock)

 /*
  * We inline the unlock functions in the nondebug case:
  */
 #if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) || \
 	!defined(CONFIG_SMP)
 # define spin_unlock(lock)		_spin_unlock(lock)
 # define read_unlock(lock)		_read_unlock(lock)
 # define write_unlock(lock)		_write_unlock(lock)
 # define spin_unlock_irq(lock)		_spin_unlock_irq(lock)
 # define read_unlock_irq(lock)		_read_unlock_irq(lock)
 # define write_unlock_irq(lock)		_write_unlock_irq(lock)
 #else
 # define spin_unlock(lock) \
     do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 # define read_unlock(lock) \
     do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 # define write_unlock(lock) \
     do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
 # define spin_unlock_irq(lock)			\
 do {						\
 	__raw_spin_unlock(&(lock)->raw_lock);	\
 	__release(lock);			\
 	local_irq_enable();			\
 } while (0)
 # define read_unlock_irq(lock)			\
 do {						\
 	__raw_read_unlock(&(lock)->raw_lock);	\
 	__release(lock);			\
 	local_irq_enable();			\
 } while (0)
 # define write_unlock_irq(lock)			\
 do {						\
 	__raw_write_unlock(&(lock)->raw_lock);	\
 	__release(lock);			\
 	local_irq_enable();			\
 } while (0)
 #endif

 #define spin_unlock_irqrestore(lock, flags) \
 					_spin_unlock_irqrestore(lock, flags)
 #define spin_unlock_bh(lock)		_spin_unlock_bh(lock)

 #define read_unlock_irqrestore(lock, flags) \
 					_read_unlock_irqrestore(lock, flags)
 #define read_unlock_bh(lock)		_read_unlock_bh(lock)

 #define write_unlock_irqrestore(lock, flags) \
 					_write_unlock_irqrestore(lock, flags)
 #define write_unlock_bh(lock)		_write_unlock_bh(lock)

 #define spin_trylock_bh(lock)	__cond_lock(lock, _spin_trylock_bh(lock))

 #define spin_trylock_irq(lock) \
 ({ \
 	local_irq_disable(); \
 	spin_trylock(lock) ? \
 	1 : ({ local_irq_enable(); 0;  }); \
 })

 #define spin_trylock_irqsave(lock, flags) \
 ({ \
 	local_irq_save(flags); \
 	spin_trylock(lock) ? \
 	1 : ({ local_irq_restore(flags); 0; }); \
 })

 #define write_trylock_irqsave(lock, flags) \
 ({ \
 	local_irq_save(flags); \
 	write_trylock(lock) ? \
 	1 : ({ local_irq_restore(flags); 0; }); \
 })

 /*
  * Locks two spinlocks l1 and l2.
  * l1_first indicates if spinlock l1 should be taken first.
  */
 static inline void double_spin_lock(spinlock_t *l1, spinlock_t *l2,
 				    bool l1_first)
 	__acquires(l1)
 	__acquires(l2)
 {
 	if (l1_first) {
 		spin_lock(l1);
 		spin_lock(l2);
 	} else {
 		spin_lock(l2);
 		spin_lock(l1);
 	}
 }

 /*
  * Unlocks two spinlocks l1 and l2.
  * l1_taken_first indicates if spinlock l1 was taken first and therefore
  * should be released after spinlock l2.
  */
 static inline void double_spin_unlock(spinlock_t *l1, spinlock_t *l2,
 				      bool l1_taken_first)
 	__releases(l1)
 	__releases(l2)
 {
 	if (l1_taken_first) {
 		spin_unlock(l2);
 		spin_unlock(l1);
 	} else {
 		spin_unlock(l1);
 		spin_unlock(l2);
 	}
 }

 /*
  * Pull the atomic_t declaration:
  * (asm-mips/atomic.h needs above definitions)
  */
 #include <asm/atomic.h>
 /**
  * atomic_dec_and_lock - lock on reaching reference count zero
  * @atomic: the atomic counter
  * @lock: the spinlock in question
  */
 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 #define atomic_dec_and_lock(atomic, lock) \
 		__cond_lock(lock, _atomic_dec_and_lock(atomic, lock))

 /**
  * spin_can_lock - would spin_trylock() succeed?
  * @lock: the spinlock in question.
  */
 #define spin_can_lock(lock)	(!spin_is_locked(lock))

 #endif /* __LINUX_SPINLOCK_H */
	#ifndef __LINUX_SPINLOCK_H
	#define __LINUX_SPINLOCK_H

	/*
	* include/linux/spinlock.h - generic spinlock/rwlock declarations
	*
	* here's the role of the various spinlock/rwlock related include files:
	*
	* on SMP builds:
	*
	* asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
	* initializers
	*
	* linux/spinlock_types.h:
	* defines the generic type and initializers
	*
	* asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel
	* implementations, mostly inline assembly code
	*
	* (also included on UP-debug builds:)
	*
	* linux/spinlock_api_smp.h:
	* contains the prototypes for the _spin_*() APIs.
	*
	* linux/spinlock.h: builds the final spin_*() APIs.
	*
	* on UP builds:
	*
	* linux/spinlock_type_up.h:
	* contains the generic, simplified UP spinlock type.
	* (which is an empty structure on non-debug builds)
	*
	* linux/spinlock_types.h:
	* defines the generic type and initializers
	*
	* linux/spinlock_up.h:
	* contains the __raw_spin_*()/etc. version of UP
	* builds. (which are NOPs on non-debug, non-preempt
	* builds)
	*
	* (included on UP-non-debug builds:)
	*
	* linux/spinlock_api_up.h:
	* builds the _spin_*() APIs.
	*
	* linux/spinlock.h: builds the final spin_*() APIs.
	*/

	#include <linux/preempt.h>
	#include <linux/linkage.h>
	#include <linux/compiler.h>
	#include <linux/thread_info.h>
	#include <linux/kernel.h>
	#include <linux/stringify.h>
	#include <linux/bottom_half.h>

	#include <asm/system.h>

	/*
	* Must define these before including other files, inline functions need them
	*/
	#define LOCK_SECTION_NAME ".text.lock."KBUILD_BASENAME

	#define LOCK_SECTION_START(extra) \
	".subsection 1\n\t" \
	extra \
	".ifndef " LOCK_SECTION_NAME "\n\t" \
	LOCK_SECTION_NAME ":\n\t" \
	".endif\n"

	#define LOCK_SECTION_END \
	".previous\n\t"

	#define __lockfunc fastcall __attribute__((section(".spinlock.text")))

	/*
	* Pull the raw_spinlock_t and raw_rwlock_t definitions:
	*/
	#include <linux/spinlock_types.h>

	extern int __lockfunc generic__raw_read_trylock(raw_rwlock_t *lock);

	/*
	* Pull the __raw*() functions/declarations (UP-nondebug doesnt need them):
	*/
	#ifdef CONFIG_SMP
	# include <asm/spinlock.h>
	#else
	# include <linux/spinlock_up.h>
	#endif

	#ifdef CONFIG_DEBUG_SPINLOCK
	extern void __spin_lock_init(spinlock_t lock, const char name,
	struct lock_class_key *key);
	# define spin_lock_init(lock) \
	do { \
	static struct lock_class_key __key; \
	\
	__spin_lock_init((lock), #lock, &__key); \
	} while (0)

	#else
	# define spin_lock_init(lock) \
	do { *(lock) = SPIN_LOCK_UNLOCKED; } while (0)
	#endif

	#ifdef CONFIG_DEBUG_SPINLOCK
	extern void __rwlock_init(rwlock_t lock, const char name,
	struct lock_class_key *key);
	# define rwlock_init(lock) \
	do { \
	static struct lock_class_key __key; \
	\
	__rwlock_init((lock), #lock, &__key); \
	} while (0)
	#else
	# define rwlock_init(lock) \
	do { *(lock) = RW_LOCK_UNLOCKED; } while (0)
	#endif

	#define spin_is_locked(lock) __raw_spin_is_locked(&(lock)->raw_lock)

	/**
	* spin_unlock_wait - wait until the spinlock gets unlocked
	* @lock: the spinlock in question.
	*/
	#define spin_unlock_wait(lock) __raw_spin_unlock_wait(&(lock)->raw_lock)

	/*
	* Pull the _spin_()/_read_()/_write_*() functions/declarations:
	*/
	#if defined(CONFIG_SMP) \|\| defined(CONFIG_DEBUG_SPINLOCK)
	# include <linux/spinlock_api_smp.h>
	#else
	# include <linux/spinlock_api_up.h>
	#endif

	#ifdef CONFIG_DEBUG_SPINLOCK
	extern void _raw_spin_lock(spinlock_t *lock);
	#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
	extern int _raw_spin_trylock(spinlock_t *lock);
	extern void _raw_spin_unlock(spinlock_t *lock);
	extern void _raw_read_lock(rwlock_t *lock);
	extern int _raw_read_trylock(rwlock_t *lock);
	extern void _raw_read_unlock(rwlock_t *lock);
	extern void _raw_write_lock(rwlock_t *lock);
	extern int _raw_write_trylock(rwlock_t *lock);
	extern void _raw_write_unlock(rwlock_t *lock);
	#else
	# define _raw_spin_lock(lock) __raw_spin_lock(&(lock)->raw_lock)
	# define _raw_spin_lock_flags(lock, flags) \
	__raw_spin_lock_flags(&(lock)->raw_lock, *(flags))
	# define _raw_spin_trylock(lock) __raw_spin_trylock(&(lock)->raw_lock)
	# define _raw_spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock)
	# define _raw_read_lock(rwlock) __raw_read_lock(&(rwlock)->raw_lock)
	# define _raw_read_trylock(rwlock) __raw_read_trylock(&(rwlock)->raw_lock)
	# define _raw_read_unlock(rwlock) __raw_read_unlock(&(rwlock)->raw_lock)
	# define _raw_write_lock(rwlock) __raw_write_lock(&(rwlock)->raw_lock)
	# define _raw_write_trylock(rwlock) __raw_write_trylock(&(rwlock)->raw_lock)
	# define _raw_write_unlock(rwlock) __raw_write_unlock(&(rwlock)->raw_lock)
	#endif

	#define read_can_lock(rwlock) __raw_read_can_lock(&(rwlock)->raw_lock)
	#define write_can_lock(rwlock) __raw_write_can_lock(&(rwlock)->raw_lock)

	/*
	* Define the various spin_lock and rw_lock methods. Note we define these
	* regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
	* methods are defined as nops in the case they are not required.
	*/
	#define spin_trylock(lock) __cond_lock(lock, _spin_trylock(lock))
	#define read_trylock(lock) __cond_lock(lock, _read_trylock(lock))
	#define write_trylock(lock) __cond_lock(lock, _write_trylock(lock))

	#define spin_lock(lock) _spin_lock(lock)

	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	# define spin_lock_nested(lock, subclass) _spin_lock_nested(lock, subclass)
	#else
	# define spin_lock_nested(lock, subclass) _spin_lock(lock)
	#endif

	#define write_lock(lock) _write_lock(lock)
	#define read_lock(lock) _read_lock(lock)

	#if defined(CONFIG_SMP) \|\| defined(CONFIG_DEBUG_SPINLOCK)

	#define spin_lock_irqsave(lock, flags) flags = _spin_lock_irqsave(lock)
	#define read_lock_irqsave(lock, flags) flags = _read_lock_irqsave(lock)
	#define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)

	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	#define spin_lock_irqsave_nested(lock, flags, subclass) \
	flags = _spin_lock_irqsave_nested(lock, subclass)
	#else
	#define spin_lock_irqsave_nested(lock, flags, subclass) \
	flags = _spin_lock_irqsave(lock)
	#endif

	#else

	#define spin_lock_irqsave(lock, flags) _spin_lock_irqsave(lock, flags)
	#define read_lock_irqsave(lock, flags) _read_lock_irqsave(lock, flags)
	#define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags)
	#define spin_lock_irqsave_nested(lock, flags, subclass) \
	spin_lock_irqsave(lock, flags)

	#endif

	#define spin_lock_irq(lock) _spin_lock_irq(lock)
	#define spin_lock_bh(lock) _spin_lock_bh(lock)

	#define read_lock_irq(lock) _read_lock_irq(lock)
	#define read_lock_bh(lock) _read_lock_bh(lock)

	#define write_lock_irq(lock) _write_lock_irq(lock)
	#define write_lock_bh(lock) _write_lock_bh(lock)

	/*
	* We inline the unlock functions in the nondebug case:
	*/
	#if defined(CONFIG_DEBUG_SPINLOCK) \|\| defined(CONFIG_PREEMPT) \|\| \
	!defined(CONFIG_SMP)
	# define spin_unlock(lock) _spin_unlock(lock)
	# define read_unlock(lock) _read_unlock(lock)
	# define write_unlock(lock) _write_unlock(lock)
	# define spin_unlock_irq(lock) _spin_unlock_irq(lock)
	# define read_unlock_irq(lock) _read_unlock_irq(lock)
	# define write_unlock_irq(lock) _write_unlock_irq(lock)
	#else
	# define spin_unlock(lock) \
	do {__raw_spin_unlock(&(lock)->raw_lock); __release(lock); } while (0)
	# define read_unlock(lock) \
	do {__raw_read_unlock(&(lock)->raw_lock); __release(lock); } while (0)
	# define write_unlock(lock) \
	do {__raw_write_unlock(&(lock)->raw_lock); __release(lock); } while (0)
	# define spin_unlock_irq(lock) \
	do { \
	__raw_spin_unlock(&(lock)->raw_lock); \
	__release(lock); \
	local_irq_enable(); \
	} while (0)
	# define read_unlock_irq(lock) \
	do { \
	__raw_read_unlock(&(lock)->raw_lock); \
	__release(lock); \
	local_irq_enable(); \
	} while (0)
	# define write_unlock_irq(lock) \
	do { \
	__raw_write_unlock(&(lock)->raw_lock); \
	__release(lock); \
	local_irq_enable(); \
	} while (0)
	#endif

	#define spin_unlock_irqrestore(lock, flags) \
	_spin_unlock_irqrestore(lock, flags)
	#define spin_unlock_bh(lock) _spin_unlock_bh(lock)

	#define read_unlock_irqrestore(lock, flags) \
	_read_unlock_irqrestore(lock, flags)
	#define read_unlock_bh(lock) _read_unlock_bh(lock)

	#define write_unlock_irqrestore(lock, flags) \
	_write_unlock_irqrestore(lock, flags)
	#define write_unlock_bh(lock) _write_unlock_bh(lock)

	#define spin_trylock_bh(lock) __cond_lock(lock, _spin_trylock_bh(lock))

	#define spin_trylock_irq(lock) \
	({ \
	local_irq_disable(); \
	spin_trylock(lock) ? \
	1 : ({ local_irq_enable(); 0; }); \
	})

	#define spin_trylock_irqsave(lock, flags) \
	({ \
	local_irq_save(flags); \
	spin_trylock(lock) ? \
	1 : ({ local_irq_restore(flags); 0; }); \
	})

	#define write_trylock_irqsave(lock, flags) \
	({ \
	local_irq_save(flags); \
	write_trylock(lock) ? \
	1 : ({ local_irq_restore(flags); 0; }); \
	})

	/*
	* Locks two spinlocks l1 and l2.
	* l1_first indicates if spinlock l1 should be taken first.
	*/
	static inline void double_spin_lock(spinlock_t l1, spinlock_t l2,
	bool l1_first)
	__acquires(l1)
	__acquires(l2)
	{
	if (l1_first) {
	spin_lock(l1);
	spin_lock(l2);
	} else {
	spin_lock(l2);
	spin_lock(l1);
	}
	}

	/*
	* Unlocks two spinlocks l1 and l2.
	* l1_taken_first indicates if spinlock l1 was taken first and therefore
	* should be released after spinlock l2.
	*/
	static inline void double_spin_unlock(spinlock_t l1, spinlock_t l2,
	bool l1_taken_first)
	__releases(l1)
	__releases(l2)
	{
	if (l1_taken_first) {
	spin_unlock(l2);
	spin_unlock(l1);
	} else {
	spin_unlock(l1);
	spin_unlock(l2);
	}
	}

	/*
	* Pull the atomic_t declaration:
	* (asm-mips/atomic.h needs above definitions)
	*/
	#include <asm/atomic.h>
	/**
	* atomic_dec_and_lock - lock on reaching reference count zero
	* @atomic: the atomic counter
	* @lock: the spinlock in question
	*/
	extern int _atomic_dec_and_lock(atomic_t atomic, spinlock_t lock);
	#define atomic_dec_and_lock(atomic, lock) \
	__cond_lock(lock, _atomic_dec_and_lock(atomic, lock))

	/**
	* spin_can_lock - would spin_trylock() succeed?
	* @lock: the spinlock in question.
	*/
	#define spin_can_lock(lock) (!spin_is_locked(lock))

	#endif /* __LINUX_SPINLOCK_H */